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PatchSiren cyber security CVE debrief

CVE-2026-47684 Sync-in CVE debrief

CVE-2026-47684 is a HIGH severity vulnerability in Sync-in Server, a secure, open-source platform for file storage, sharing, collaboration, and syncing. The bug allows for SSRF protection bypass on dual-stack systems due to a flawed private IP blocklist regex used in the URL download feature, which fails to match IPv4-mapped IPv6 addresses. This issue was fixed in version 2.3.0.

Vendor
Sync-in
Product
server
CVSS
HIGH 7.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-16
Original CVE updated
2026-06-16
Advisory published
2026-06-16
Advisory updated
2026-06-16

Who should care

Users of Sync-in Server versions prior to 2.3.0 should upgrade to 2.3.0 to fix the vulnerability.

Technical summary

The private IP blocklist regex used in the URL download feature of Sync-in Server does not match IPv4-mapped IPv6 addresses (e.g., ::ffff:127.0.0.1), allowing SSRF protection to be bypassed on dual-stack systems. This was fixed in version 2.3.0.

Defensive priority

HIGH

Recommended defensive actions

  • Upgrade to Sync-in Server version 2.3.0 or later.

Evidence notes

The CVE-2026-47684 record was published on [cve-org](https://www.cve.org/CVERecord?id=CVE-2026-47684). Details can be found on [nvd](https://nvd.nist.gov/vuln/detail/CVE-2026-47684).

Sources and references

Verified primary and authoritative sources

  • CVE-2026-47684 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-47684

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-47684 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-47684

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.